Process and composition containing an oxygen releasing compound and an organic carbonate



United States Patent Ofiice Patented Sept. 13, 1966 Maine N Drawing. Filed May 3, 1963, Ser. No. 277,721 Claims priority, application Great Britain, May 7, 1962, 17 379/ 62 11 Claims. (31. 252-99 This invention relates to processes of bleaching and to bleaching compositions; in particular it relates to processes and to compositions suitable for removing stains from textile materials.

Many detergene compositions contain an inorganic persalt such as sodium perborate or percarbonate to provide bleaching properties. These per-salts provide a satisfactory bleach when the detergent is used at the boil, but at lower temperatures their action is rather slow. This disadvantage is becoming important with the growing use of washing machines Which operate at a temperatom of, for example, 50-60 C. It is an object of the present invention to provide a more effective bleach in the normal washing period at this temperature than is obtained with the per-salt alone.

Processes and compositions according to the invention also find application in the textile industry and in commercial laundering.

It has been found that improvements in bleaching can be obtained by the use of an aqueous solution containing hydrogen peroxide and an ester of carbonic acid or pyrocarbonic acid as characterised below.

It has further been found that improved bleaching compositions can be provided which contain an inorganic persalt together with an ester of carbonic acid or pyrocarbonic acid. The esters which are suitable for use in the invention are characterised by the following per-acid formation test.

To a solution at 60 C. containing the following 500 ml. distilled water:

1.25 grams sodium pyroph-osphate decahydrate (Na P O 1 0.154 gram sodium perborate (NaBO .H O .3H O) (at 10.4% available oxygen) is added an amount of ester, in equimolecular ratio to the available oxygen. Water soluble esters are added direct to the aqueous solution; other esters should be dissolved in 10 ml. ethyl alcohol before addition, the volume of distilled water being reduced in such cases to 490 ml. Acidic derivatives should be neutralised before addition. The mixture is mechanically stirred by means of a glass stirrer at 600 revolutions per minute and maintained at 60 C. After one minute and after five minutes 100 ml. portions are withdrawn and immediately pipetted onto a mixture of 250 grams of cracked ice and ml. of glacial acetic acid. 0.4 gram of potassium iodide is then added. The liberated iodine is immediately titrated with 0.1 N-sodium thiosulphate, using starch as indicator, until the first disappearance of the blue colour.

Esters which may be used in bleaching compositions and processes of the invention are those which give a titre of 1.0 millilitres or more in this test after one minute or after five minutes, or both.

According to the present invention there is provided a bleaching process in which is used an aqueous solution of hydrogen peroxide and an ester of carbonic acid or pyrocarbonic acid which gives a titre of not less than 1.0 millilitres of 0.1 N sodium thiosulphate in the test defined above.

The present invention further provides a bleaching composition which contains an inorganic per-salt together with an ester of carbonic acid or pyrocarbonic acid which gives a titre of not less than 1.0 ml. of 0.1 N sodium thiosulphate in the test defined above.

Esters which give a titre of not less than 1.0 ml. of 0.1 N sodium th'iosulphate in the test defined above and hence may be used according to the invention include compounds Within the class R O.CO.OR in which R exerts an electron attracting effect and R is an alkyl, aryl, or alicyclic radical or a substituted alkyl, aryl or alicyclic radical.

The esters should not yield easily oxidisable hydrolysis products such as polyhydric phenols.

Examples of esters within the scope of the invention, that is those which give a titre of at least 1.0 ml. of 0.1 N sodium thiosulphate in the test defined above, are:

sodium p-sulphophenyl ethyl carbonate sodium p-sulphophenyl methyl carbonate sodium p-sulphophenyl phenyl carbonate diethyl pyrocarbonate p-carboxyphenyl ethyl carbonate p-carboxyphenyl methyl carbonate p-carboxyphenyl phenyl carbonate o-carboxyphenyl ethyl carbonate o-carboxyphenyl methyl carbonate p-carboxyphenyl n-propyl carbonate p-carboxyphenyl n-butyl carbonate benzyl p-carboxyphenyl carbonate sodium p-sulphophenyl n-propyl carbonate sodium p-sulphophenyl n-butyl carbonate sodium p-sulphophenyl benzyl carbonate Hydrogen peroxide cannot, of course, be included in a solid composition, and bleaching solutions prepared from hydrogen peroxide should be prepared as required for use. The hydrogen peroxide may be added to the solution as such, or may be liberated in situ from a per-salt.

By inorganic per-salt is meant a salt which will give rise to hydrogen peroxide in aqueous solution. Suitable compounds are alkali metal perborates, percarbonates, perpyrophosphates and persilicates. These are believed not to be true per-salts in the strict chemical sense but to contain hydrogen peroxide of crystallisation, which is liberated in aqueous solution.

The invention can be applied to bleaching baths such as are used for treating textiles, to wash liquors, such are used in comercial laundering and to solid bleaching compositions. Solid bleaching compositions may contain, in addition to a per-salt and an ester according to the invention, inert salts, alkaline agents and a small proportion of detergent. The invention may further be applied to detergent compositions, which contain an organic detergent, which may be soap or an organic soapless detergent. Suitable organic soap'less detergents are the alkylaryl sulphonates, alkyl sulphates and the salts of esters or ethers of isethionic acid. Compositions according to the invention should preferably contain one or more alkaline substances in amounts such that similar compositions not containing esters would give a pH value within the range 9-11 when dissolved at the desired bleaching concentration. Most common detergent compositions contain alkaline material sufiicient for this purpose. Suitable alkaline materials are, for instance, soap, alkali-metal carbonates, phosphates (including orthophosphates and water-soluble condensed phosphates, such as tripolyphospirates and pyrophosphates) and silicates.

When the invention is applied to bleaching or wash liquors, alkali sufficient to give an initial pH of 9-11 is preferably present in the bleaching or Wash liquor before addition of the ester.

Compositions according to the invention may contain any of the conventional adjuncts present in detergent compositions. There may be mentioned, supplementary builders, inert and organic materials such as alkali metal sulphates, chlorides, carboxyrnethylcellulose and fluorescent agents.

Compositions according to the invention must not contain water in an amount sufiicient to permit appreciable chemical reaction between the components prior to use.

The proportions of per-salt and ester which may be present in compositions according to the invention will depend on the time and temperature of bleaching, the degree of bleaching required, the concentration of the bleaching solution and the individual ester and per-salt used. Under most conditions, these proportions should be such as to give a per-salt concentration in solution equivalent to 0.001 to 0.1% available oxygen.

Having regard to these factors, bleaching effects may be obtained with compositions according to the invention containing widely varying ratios of per-salt to ester. It is convenient to measure the activity of the per-salt in terms of available oxygen. Generally ratios of from A to 2 and particularly from /2 to 1 /2. molecules of ester per 1 atom of available oxygen are preferred. (In converting such ratios to ratios by weight, account must be taken of the molecular weight of the ester and the avialable oxygen content of the per-salt used.) In particular, it is preferred to use approximately chemically equivalent amounts of ester and per-salt.

When solutions are used which are obtained by adding hydrogen peroxide and an ester according to the invention to an alkaline bath, the preferred weight ratio is from 2 to 15 parts of ester to 1 part of hydrogen peroxide (100%) depending on the molecular Weight of the ester used.

When compositions according to the invention are to be used primarily as a bleach, for instance, for addition to alkaline textile bleaching baths or wash liquors, such compositions may contain any proportion of ester and per-salt, these components being preferably present in the ratio of M1. to 2 molecules of ester per 1 atom of available oxygen, preferably /2 to 1 /2 molecules per 1 atom of available oxygen.

When an organic detergent is present in compositions of the invention, improvements in bleaching can be obtained at normal washing concentrations. Thus, for example, using a detergent composition of the invention at a concentration of 1% in aqueous solution improvements may be obtained if amounts of as little as 1% of persalt and 2% of ester by weight of the composition are present. In such compositions, the amount of per-salt taken should provide at least 0.1% available oxygen based on the composition. Generally, detergent compositions will contain from about to about 50% by Weight of organic detergent. The mixed ester/per-salt content may be as high as 70% by weight provided that these components are taken in ratios of A to 2, preferably /2 to 1 /2 molecules of ester per 1 atom of available oxygen. Etfective proportions of ester and per-salt in detergent compositions will lie in general within the range of 2% to 30% of ester and 1% to 75% of per-salt by weight of the composition.

Best results in bleaching according to the invention are obtained under conditions of effective agitation such as exist, for instance, in a washing machine.

The following exampie illustrates the invention:

Example Bleaching solutions were prepared containing:

Percent Sodium dodecyl benzene sulphonate 0.054 Coconut mono-ethanolamide 0.018 Sodium tripolyphosphate 0.115 Sodium sulphate 0.045 Anhydrous alkaline sodium silicate 0.029 Sodium carboxymethylcellulose 0.004 Sodium perborate tetrahydrate 0.032

and an ester in concentration as given in the table below. The carboxylic acids were converted to their sodium salts immediately before use.

A length of cotton cloth was stained by immersion in boiling tea extract for one hour. It was then thoroughly rinsed, dried and cut into pieces whose percent refiectances were measured in a Hunter reflectometer using the blue filter. The percent reflectance of the test pieces was measured again after bleaching. The bleach obtained 'was expressed as the difference in the two percent readings on each test-piece.

A piece of stained cloth was immersed in each of the freshly-prepared bleaching solutions at 60 C. for 10 minutes with stirring. The cloths were then removed from the solutions, rinsed three times in distilled water, ironed and their reflectance measured. The results are given in the following table.

Increase in Ooncentra- Increase in percent Ester tion of ester percent reflectance in solution reflectance in absence (percent) of ester (control) Sodium p-sulphophenyl ethyl carbonate 0. 054 19. 1 12. 6 pCarboxyphenyl ethyl carbonate 0. 042 17. 9 12. 6 p-Carboxyphenyl methyl carbonate 0. 039 15. 1 11.3 p-Carboxyphenyl phenyl carbonate 0. 052 19. 0 11. 9 o-Carboxyphenyl ethyl carbonate 0. 042 13.6 11.3 o-Carboxyphenyl methyl carbonate 0. 039 13. 6 11. 3 Diethyl pyrccarbonatc 0. 032 22. 5 15. 9 p-Carboxyphenyl n-propyl carbonate -1 0. 045 20. 7 15. 0 p-Oarboxyphenyl n-butyl carbonate 0. 048 16.3 10. 6 Benzyl p-carboxyphenyl carbonate 0. 054 16. 4 10. 6 Sodium p-sulphophenyl npropyl carbonate 0. 056 21. 6 15. 9 Sodium p-sulphophenyl n-butyl carbonate 0. 060 18. 4 10. 6 Sodium p-sulphophenyl benzyl carbonate 0. 066 17. 5 l0. 6

The esters other than p-carboxyphenyl phenyl carbonate and diethyl pyrocarbonate can be prepared by reacting an alkyl chloroformate and a pehnol.

I claim:

1. A process for bleaching textile materials comprising the step of placing the article to be bleached in an aqueous solution of hydrogen peroxide and an ester selected from the class consisting of (a) esters of carbonic acid having the formula R O-COOR wherein each of R and R is an organic radical, R exerting an electron attracting effect, and (b) diethyl pyrocarbonate, said esters having a titer in the per-acid formation test of not less than 1.0 ml. of 0.1 N Na S O the hydrogen peroxide and ester being present in amounts suflicient to provide from about A to about 2 molecules of ester per atom of available oxygen.

2. A process according to claim 8 in which said aqueous solution has an initial pH between 9 and 11.

3. A process for bleaching soiled textile material comprising the steps of placing the article to be bleached in an aqueous solution of hydrogen peroxide and an ester selected from the class consisting of (a) esters of carbonic acid having the formula R OCOOR wherein each of R and R is an organic radical, R exerting an electron attracting effect, and (b) diethyl pyrocarbonate, said esters having a titer in the per-acid formation test of not less than 1.0 ml. of 0.1 N N21 S O the hydrogen peroxide and ester being present in an amount sufiicient to provide from about A to about 2 molecules of ester per atom of available oxygen, allowing the said article to remain in said solution at a temperature substantially below the boiling point thereof for a normal washing period, and rinsing the article.

4. A composition for use in bleaching textile material consisting essentially of an inorganic per-salt selected from the group consisting of the alkali metal perborates, percarbonates, perpyrophosphates, and persilicates, and an ester selected from the class consisting of (a) esters of carbonic acid having the formula R -O-COOR wherein each of R and R is an organic radical, R exerting an electron-attracting effect, and (b) diethyl pyrocarbonate, said esters having a titer in the per-acid formation test of not less than 1.0 ml. of 0.1 N Na S O the hydrogen peroxide and ester being present in amounts sufiicient to provide from about A to about 2 molecules of ester per atom of available oxygen.

5. A composition according to claim which exhibits a pH between about 9 and about 11 when placed in an aqueous solution.

6. A composition according to claim 10 wherein said ester and said inorganic per-salt are present in amounts sufiicient to provide from about /2 to about 1 /2 molecules of ester per atom of available oxygen.

7. A composition for bleaching textile material which is an aqueous solution of hydrogen peroxide and an ester selected from the group consisting of (a) esters of carbonic acid having the formula R O-CO-O-R wherein each of R and R is an organic radical, R exerting an electron-attracting effect, and (b) diethyl pyrocarbonate, said esters having a titer in the per-acid formation test of not less than 1.0 ml. of 0.1 N Na S O the hydrogen peroxide and ester being present in amounts sufficient to provide from about A to about 2 molecules of ester per atom of available oxygen.

8. A process for bleaching textile materials comprising the steps of placing the article to be bleached in an aqueous solution of hydrogen peroxide and an ester selected from the class consisting of sodium p-sulfophenyl ethel carbonate, sodium p-sulfophenyl methyl carbonate, sodium p-sulfophenyl phenyl carbonate, diethyl pyrocarbonate, p-carboxyphenyl ethyl carbonate, p-carboxyphenyl methyl carbonate, p-carboxyphenyl phenyl carbonate, o-carboxyphenyl ethyl carbonate, o-carboxyphenyl methyl carbonate, p-carboxyphenyl n-propyl carbonate, p-carboxyphenyl n-butyl carbonate, benzyl pcarboxyphenyl carbonate, sodium p-sulfophenyl n-propyl carbonate, sodium p-sulfophenyl n-butyl carbonate and sodium p-sulfophenyl benzyl carbonate, said esters having a titer in the per-acid formation test of not less than 1.0 ml. of 0.1 N Na S O the hydrogen peroxide and ester being present in an amount sufiicient to provide from about A to about 2 molecules of ester per atom of available oxygen.

9. A process according to claim 8, including the additional steps of allowing said article to remain in said solution at a temperature substantially below the boiling point thereof for a normal washing period, and thereafter rinsing said article.

10. A composition for use in bleaching textile materials consisting essentially of an inorganic per-salt selected from the group consisting of the alkali metal perborates, percarbonates, perpyrophosphates, and persilicates, and an ester selected from the class consisting of sodium p-sulfophenyl ethyl carbonate, sodium p-sulfophenyl methyl carbonate, sodium p-sulfophenyl phenyl carbonate, diethyl pyrocarbonate, p-carboxyphenyl ethyl carbonate, p-carboxyphenyl methyl carbonate, p-carboxyphenyl phenyl carbonate, o-carboxyphenyl ethyl carbonate, o-carboxyphenyl methyl carbonate, p-carboxyphenyl n-propyl carbonate, p-carboxyphenyl n-butyl carbonate, benzyl p-carboxyphenyl carbonate, sodium p-sulfophenyl n-propyl carbonate, sodium p-sulfophenyl nbutyl carbonate and sodium p-sulfophenyl benzyl carbonate, said esters having a titer in the per-acid formation test of not less than 1.0 ml. of 0.1 N Na S O the hydrogen peroxide and ester being present in amounts suflicient to provide from about A to about 2 molecules of ester per atom of available oxygen.

11. A composition for bleaching textile materials which is an aqueous solution of hydrogen peroxide and an ester selected from the group consisting of sodium p-sulfophenyl ethyl carbonate, sodium p-sulfophenyl methyl carbonate, sodium p-sulfophenyl phenyl carbonate, diethyl pyrocarbonate, p-carboxyphenyl ethyl carbonate, pcarboxyphenyl methyl carbonate, p-carboxyphenyl phenyl carbonate, o-carboxyphenyl ethyl carbonate, o-carboxyphenyl methyl carbonate, p-carboxyphenyl n-propyl carbonate, p-carboxyphenyl n-butyl carbonate, benzyl p-carboxyphenyl carbonate, sodium p-sulfophenyl n-propyl carbonate, sodium p-sulfophenyl n-butyl carbonate and sodium p-sulfophenyl benzyl carbonate, said esters having a titer in the per-acid formation test of not less than 1.0 ml. of 0.1 N Na S O the hydrogen peroxide and ester being present in an amount sufiicient to provide from about A to about 2 molecules of ester per atom of available oxygen.

References Cited by the Examiner UNITED STATES PATENTS 2,770,639 11/1956 Slocorrrbe et a1 260-463 2,837,555 6/1958 Lee 260463 2,843,567 7/1958 Williams et a1. 260-463 XR 2,916,345 12/1959 Hess 260463 XR 3,017,424 1/1962 Meyer et al 260-463 3,078,294 2/1963 Howe et al. 260463 XR FOREIGN PATENTS 836,988 6/1960 Great Britain.

LEON D. ROSDOL, Primary Examiner.

JULIUS GREENWALD, Examiner.

M. WEINBLATT, Assistant Examiner,

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Noe 3,272,750 September 13, 1966 Basil Hugh Chase It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 41, after "following" insert in column 3, lines 25 and 26, for "avialable" read available column 3, line 60, for "75%" read 15% column 4,

line 45, for "pehnol" read phenol --o Signed and sealed this 29th day of August 1967o (SEAL) Atteat: ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

4. A COMPOSITION FOR USE IN BLEACHING TEXTILE MATERIAL CONSISTING ESSENTIALLY OF AN INORGANIC PER-SALT SELECTED FROM THE GROUP CONSISTING OF THE ALKALI METAL PERBORATES PERCARBONATES, PERPYROPHOSPHATES, AND PERSILICATE, AND AN ESTER SELECTED FROM THE CLASS CONSISTING OF (A) ESTER OF CARBONIC ACID HAVING THE FORMULA R1-O-CO-O-R2 WHEREIN EACH OF R1 AND R2 IS AN ORGANIC RADICAL, R1 EXERTING AN ELECTRON-ATTRACTING EFFECT, AND (B) DIETHYL PYROCARBONATE, SAID ESTERS HAVING A TITER IN THE PER-ACID FORMATION TEST OF NOT LESS THAN 1.0 ML. OF 0.1 N NA2S2O3, THE HYDROGEN PEROXIDE AND ESTER BEING PRESENT IN AMOUNTS SUFFICIENT TO PROVIDE FROM ABOUT 1/4 TO ABOUT 2 MOLECULES OF ESTER PER ATOM OF AVAILABLE OXYGEN. 